Eckols are a special class of polyphenols derived from brown algae, which are known as phlorotannins and are characterized by a dibenzo-1,4-dioxin unit in the molecular skeleton which is found only in some specific algae such as Eisenia and Ecklonia species. Importantly, eckols have the unusual ability to penetrate the blood brain barrier and have a diverse array of biological activities.
Exemplary eckols include 2-O-(2,4,6-trihydroxyphenyl) 6,6′ bieckol, 6,6′ bieckol, 8,8, bieckol, phlorofucofuroeckol A, fucofuroeckol A, dioxinodehydroeckol, dieckol, eckol, 2-phloroeckol and 7-phloroeckol, the structures of which are depicted below.

Noteworthy of the above structures is that the eckols, in general, all possess the core structure of eckol, which is regioselectively modified with additional phenolic groups to provide the compounds above.
Given the impressive biological activity of the natural eckols, it is necessary to prepare synthetically modified eckols which may possess superior biological activity against various medical disorders.